US4514682A - Secondary electron spectrometer for measuring voltages on a sample utilizing an electron probe - Google Patents
Secondary electron spectrometer for measuring voltages on a sample utilizing an electron probe Download PDFInfo
- Publication number
- US4514682A US4514682A US06/398,542 US39854282A US4514682A US 4514682 A US4514682 A US 4514682A US 39854282 A US39854282 A US 39854282A US 4514682 A US4514682 A US 4514682A
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- United States
- Prior art keywords
- secondary electrons
- electron
- spectrometer
- grating
- measuring
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J49/00—Particle spectrometers or separator tubes
- H01J49/02—Details
- H01J49/08—Electron sources, e.g. for generating photo-electrons, secondary electrons or Auger electrons
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J49/00—Particle spectrometers or separator tubes
- H01J49/44—Energy spectrometers, e.g. alpha-, beta-spectrometers
Definitions
- the present invention relates to an improvement in a secondary electron spectrometer utilizing an electron beam probe.
- the angle distribution of the secondary electrons is, however, not taken into consideration in such conventional devices.
- the angle distribution may, however, be changed due to electrostatic microfields at the surface of the specimen, that is, when the potential changes at the measurement point the local microfield at the specimen surface also changes, as does the angle distribution of the secondary electrons. Because secondary electron spectrometers of the type described in the above-identified article do not perceive the change in the angular distribution of the secondary electrons, measuring errors of approximately 5% through 10% occur.
- a secondary electron spectrometer constructed in accordance with the principles of the present invention also exhibits marked measuring sensitivity.
- the single FIGURE is a side view of the operative portion of a secondary electron spectrometer constructed in accordance with the principles of the present invention.
- a secondary electron spectrometer constructed in accordance with the principles of the present invention which takes the angular distribution of the emitted secondary electrons into consideration in undertaking a measurement of voltages at various points on a sample is shown in the FIGURE.
- This improved secondary electron spectrometer may be utilized in an electron beam measuring installation as is described in the above-identified article of the inventor.
- the secondary electrons SE are extracted from the sample PR, which may be an integrated circuit chip, by an extraction field A1 having a high field strength.
- the extraction field A1 is disposed between a first grating G1 and the specimen PR.
- the measuring points on the specimen PR are generally at zero potential in their non-activated state whereas, as is described in the above-identified article, the grating G1 is at a high potential such as, for example, 600 volts.
- the secondary electrons SE traverse a decelerating opposing field BF disposed between the first grating G1 and a second grating G2.
- the grating G2 is at approximately the same potential as the measuring points on the specimen PR in their non-activated state.
- the decelerating opposing field BF between the gratings G1 and G2 is of such a nature that the field only partially cancels the preceding acceleration imparted by the extraction field A1.
- all secondary electrons SE can traverse the grating G2 and exhibit an angular distribution which is identical to the angular distribution of the secondary electrons SE at the surface of the specimen PR.
- the energy distribution of the secondary electrons SE can then be measured without error, by taking the angular distribution of the secondary electrons into consideration, by means of a hemispherically symmetrical (isotropic) grating G3.
- the hemispherically symmetrical grating G3 is at a potential of approximately -7 volts in the sample embodiment shown in the drawing.
- the secondary electrons SE are then again accelerated by a second extraction field A2 by means of a further grating G4 toward a schematically represented detector D.
- the grating G4 is operated at substantially the same voltage as in the secondary electron spectrometer described in the article, i.e., 120 V.
- the secondary electron spectrometer is provided with shielding AB.
- the primary electrons PE of the electron beam which are incident upon the specimen PR generate secondary electrons SE with a specific angular distribution dependent on the potential at the measuring point on the specimen surface. Horizontal and arced equipotential lines within the secondary electron spectrometer are indicated by the aligned dots.
- the device disclosed and claimed herein is particularly suited for quantitative voltage measurements taken at various nodes of an integrated circuit utilizing an electron probe.
- a significant feature of the structure disclosed herein is the projection of the angular distribution of the secondary electrons SE existing at the specimen surface, which is dependent upon the potential appearing at the measuring point on the specimen surface, onto the plane of the grating G2.
- the secondary electrons SE exhibit essentially the same three-dimensional pulse distribution as at the measuring point on the specimen surface at the time the secondary electrons SE are first generated by the primary electrons PE.
- the secondary electrons SE are accelerated with this three-dimensional distribution after passage through the grating G2 in such a manner that the change in the angular distribution due to a potential change at the measuring point on the specimen surface does not falsify the measurement of the energy distribution of the secondary electrons SE at the detector.
- the secondary electrons SE are decelerated in the opposing field GF between the second grating G2 and the spherically symmetric isotropic grating G3 independently of their direction of travel and only as a function of their energy.
- the voltage of approximately -7 volts of the grating G3 is selected such that, given a voltage of the measuring points situated on the specimen PR of approximately 8 volts in the activated state (measuring points in their non-activated state being at zero potential) secondary electrons SE emitted at such activated measuring points still proceed to the second extraction field A2 independently of their direction of travel and subsequently proceed to a detector via the further grating G4.
- the inventive concept disclosed and claimed herein is not restricted to the sample embodiment shown in the drawing.
- the distinguishing feature of the invention is an electron spectrometer which determines the energy distribution of the secondary electrons SE independently of their angular distribution.
- the effects of the gratings G1, G2 and G3 may also be achieved by means of only two appropriately shaped gratings, the first grating being designed as an extraction grating and the second grating being designed as a deceleration grating.
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- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Analysing Materials By The Use Of Radiation (AREA)
- Testing Or Measuring Of Semiconductors Or The Like (AREA)
- Electron Tubes For Measurement (AREA)
- Testing Of Individual Semiconductor Devices (AREA)
- Tests Of Electronic Circuits (AREA)
Abstract
An improved secondary electron spectrometer for measuring voltages occurring on a specimen, such as an integrated circuit chip, utilizing an electron probe has a grating structure for measuring the energy distribution of the secondary electrons independently of the angular distribution of the secondary electrons at the measuring point on the specimen. If the secondary electron spectrometer has an extraction electrode and a deceleration electrode, the grating structure is spherically symmetric.
Description
1. Field of the Invention
The present invention relates to an improvement in a secondary electron spectrometer utilizing an electron beam probe.
2. Description of the Prior Art
The use of secondary electron spectrometers for undertaking voltage measurements at various locations of very small specimens, such as an integrated circuit chip, which utilize an electron probe is described, for example, in an article by the inventor herein entitled "VLSI Testing Using the Electron Probe," Scanning Electron Microscopy/1979, pages 285-296. The basic principle utilized in conducting voltage measurements at various circuit nodes utilizing an electron beam probe is that the voltage present at the circuit node causes the emission of secondary electrons, with the energy of the emitted secondary electrons being an indication of the voltage at the measurement point. The secondary electrons emitted at the sample pass through an extraction field and are subsequently decelerated in a homogenous opposing field. The result obtained from this conventional opposing field spectrometer is an integral energy distribution. The angle distribution of the secondary electrons is, however, not taken into consideration in such conventional devices. The angle distribution may, however, be changed due to electrostatic microfields at the surface of the specimen, that is, when the potential changes at the measurement point the local microfield at the specimen surface also changes, as does the angle distribution of the secondary electrons. Because secondary electron spectrometers of the type described in the above-identified article do not perceive the change in the angular distribution of the secondary electrons, measuring errors of approximately 5% through 10% occur.
It is an object of the present invention to provide a secondary electron spectrometer utilizing an electron beam probe which has an improved measuring precision by virtue of the inclusion of a means for measuring the energy distribution of the secondary electrons independently of the angular distribution of the secondary electrons at the measuring point on the sample.
In addition to improved measuring precision, a secondary electron spectrometer constructed in accordance with the principles of the present invention also exhibits marked measuring sensitivity.
The single FIGURE is a side view of the operative portion of a secondary electron spectrometer constructed in accordance with the principles of the present invention.
A secondary electron spectrometer constructed in accordance with the principles of the present invention which takes the angular distribution of the emitted secondary electrons into consideration in undertaking a measurement of voltages at various points on a sample is shown in the FIGURE. This improved secondary electron spectrometer may be utilized in an electron beam measuring installation as is described in the above-identified article of the inventor.
In the secondary electron spectrometer disclosed and claimed herein, the secondary electrons SE are extracted from the sample PR, which may be an integrated circuit chip, by an extraction field A1 having a high field strength. The extraction field A1 is disposed between a first grating G1 and the specimen PR. The measuring points on the specimen PR are generally at zero potential in their non-activated state whereas, as is described in the above-identified article, the grating G1 is at a high potential such as, for example, 600 volts.
After passing through the extraction field A1, the secondary electrons SE traverse a decelerating opposing field BF disposed between the first grating G1 and a second grating G2. As is also known from the above-identified article, the grating G2 is at approximately the same potential as the measuring points on the specimen PR in their non-activated state.
The decelerating opposing field BF between the gratings G1 and G2 is of such a nature that the field only partially cancels the preceding acceleration imparted by the extraction field A1. Thus, all secondary electrons SE can traverse the grating G2 and exhibit an angular distribution which is identical to the angular distribution of the secondary electrons SE at the surface of the specimen PR. The energy distribution of the secondary electrons SE can then be measured without error, by taking the angular distribution of the secondary electrons into consideration, by means of a hemispherically symmetrical (isotropic) grating G3. The hemispherically symmetrical grating G3 is at a potential of approximately -7 volts in the sample embodiment shown in the drawing. The secondary electrons SE are then again accelerated by a second extraction field A2 by means of a further grating G4 toward a schematically represented detector D. The grating G4 is operated at substantially the same voltage as in the secondary electron spectrometer described in the article, i.e., 120 V. The secondary electron spectrometer is provided with shielding AB. The primary electrons PE of the electron beam which are incident upon the specimen PR generate secondary electrons SE with a specific angular distribution dependent on the potential at the measuring point on the specimen surface. Horizontal and arced equipotential lines within the secondary electron spectrometer are indicated by the aligned dots.
The device disclosed and claimed herein is particularly suited for quantitative voltage measurements taken at various nodes of an integrated circuit utilizing an electron probe.
A significant feature of the structure disclosed herein is the projection of the angular distribution of the secondary electrons SE existing at the specimen surface, which is dependent upon the potential appearing at the measuring point on the specimen surface, onto the plane of the grating G2. The secondary electrons SE exhibit essentially the same three-dimensional pulse distribution as at the measuring point on the specimen surface at the time the secondary electrons SE are first generated by the primary electrons PE. The secondary electrons SE are accelerated with this three-dimensional distribution after passage through the grating G2 in such a manner that the change in the angular distribution due to a potential change at the measuring point on the specimen surface does not falsify the measurement of the energy distribution of the secondary electrons SE at the detector. The secondary electrons SE are decelerated in the opposing field GF between the second grating G2 and the spherically symmetric isotropic grating G3 independently of their direction of travel and only as a function of their energy. The voltage of approximately -7 volts of the grating G3 is selected such that, given a voltage of the measuring points situated on the specimen PR of approximately 8 volts in the activated state (measuring points in their non-activated state being at zero potential) secondary electrons SE emitted at such activated measuring points still proceed to the second extraction field A2 independently of their direction of travel and subsequently proceed to a detector via the further grating G4.
The inventive concept disclosed and claimed herein is not restricted to the sample embodiment shown in the drawing. The distinguishing feature of the invention is an electron spectrometer which determines the energy distribution of the secondary electrons SE independently of their angular distribution. The effects of the gratings G1, G2 and G3 may also be achieved by means of only two appropriately shaped gratings, the first grating being designed as an extraction grating and the second grating being designed as a deceleration grating.
Although modifications and changes may be suggested by those skilled in the art it is the intention of the inventor to embody within the patent warranted hereon all changes and modifications as reasonably and properly come within the scope of this contribution to the art.
Claims (1)
1. A secondary electron spectrometer for detecting the energy distribution of secondary electrons from a measuring point on a sample independent of the angular distribution of said secondary electrons, said spectrometer inclucing an electron detector and comprising in sequence between said sample and said detector;
an extraction electrode generating an extraction field for accelerating said secondary electrons from said sample;
a deceleration electrode generating a deceleration field for decelerating said secondary electrons after passing through said extraction field;
a hemispherically symmetrical electrode generating another deceleration field for further decelerating said secondary electrons, said hemispherically symmetrical electrode isotropically decelerating said secondary electrons; and
an acceleration electrode generating another extraction field for accelerating said secondary electrons toward said detector.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE3138929 | 1981-09-30 | ||
DE19813138929 DE3138929A1 (en) | 1981-09-30 | 1981-09-30 | IMPROVED SECONDARY ELECTRON SPECTROMETER FOR POTENTIAL MEASUREMENT ON A SAMPLE WITH AN ELECTRON PROBE |
Publications (1)
Publication Number | Publication Date |
---|---|
US4514682A true US4514682A (en) | 1985-04-30 |
Family
ID=6143065
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US06/398,542 Expired - Fee Related US4514682A (en) | 1981-09-30 | 1982-07-15 | Secondary electron spectrometer for measuring voltages on a sample utilizing an electron probe |
Country Status (4)
Country | Link |
---|---|
US (1) | US4514682A (en) |
EP (1) | EP0075709B1 (en) |
JP (1) | JPS5871542A (en) |
DE (2) | DE3138929A1 (en) |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4658137A (en) * | 1983-10-17 | 1987-04-14 | Texas Instruments Incorporated | Electron detector |
US4812651A (en) * | 1986-11-13 | 1989-03-14 | Siemens Aktiengesellschaft | Spectrometer objective for particle beam measuring instruments |
US5093616A (en) * | 1989-09-14 | 1992-03-03 | Hitachi, Ltd. | Voltage measurement method using electron beam |
US6359451B1 (en) | 2000-02-11 | 2002-03-19 | Image Graphics Incorporated | System for contactless testing of printed circuit boards |
US6621274B2 (en) | 2000-02-14 | 2003-09-16 | Image Graphics Incorporated | System for contactless testing of printed circuit boards |
US20180082829A1 (en) * | 2016-01-21 | 2018-03-22 | Japan Synchrotron Radiation Research Institute | Retarding potential type energy analyzer |
EP3203494A4 (en) * | 2014-09-24 | 2018-06-06 | National Institute for Materials Science | Energy-discrimination electron detector and scanning electron microscope in which same is used |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS59211953A (en) * | 1983-05-17 | 1984-11-30 | Univ Osaka | Secondary electron spectral device |
JPS63126148A (en) * | 1986-11-14 | 1988-05-30 | Hiroshi Daimon | Charged particle analyzer |
JP2696216B2 (en) * | 1988-01-11 | 1998-01-14 | セイコーインスツルメンツ株式会社 | Ion beam processing equipment |
Citations (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2946002A (en) * | 1958-02-17 | 1960-07-19 | Kingston Electronic Corp | Signal-pickup test probe |
US3445708A (en) * | 1967-02-06 | 1969-05-20 | Gen Electric | Electron diffraction unit |
US3448377A (en) * | 1967-10-12 | 1969-06-03 | Atomic Energy Commission | Method utilizing an electron beam for nondestructively measuring the dielectric properties of a sample |
US3531716A (en) * | 1967-06-16 | 1970-09-29 | Agency Ind Science Techn | Method of testing an electronic device by use of an electron beam |
US3549999A (en) * | 1968-06-05 | 1970-12-22 | Gen Electric | Method and apparatus for testing circuits by measuring secondary emission electrons generated by electron beam bombardment of the pulsed circuit |
US3760180A (en) * | 1971-10-14 | 1973-09-18 | Siemens Ag | Electron-beam micro-analyzer with an auger electron detector |
US3796947A (en) * | 1973-02-27 | 1974-03-12 | Bell Telephone Labor Inc | Electron beam testing of film integrated circuits |
US4179604A (en) * | 1978-09-29 | 1979-12-18 | The United States Of America As Represented By The Secretary Of The Navy | Electron collector for forming low-loss electron images |
US4355232A (en) * | 1979-05-28 | 1982-10-19 | Hitachi, Ltd. | Apparatus for measuring specimen potential in electron microscope |
US4417203A (en) * | 1981-05-26 | 1983-11-22 | International Business Machines Corporation | System for contactless electrical property testing of multi-layer ceramics |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1946931A1 (en) * | 1969-09-17 | 1971-03-18 | Gen Electric | Method for testing circuits and devices for carrying out the method |
JPS4823385A (en) * | 1971-07-28 | 1973-03-26 | ||
US4169244A (en) * | 1978-02-03 | 1979-09-25 | Plows Graham S | Electron probe testing, analysis and fault diagnosis in electronic circuits |
DE2814049A1 (en) * | 1978-03-31 | 1979-10-18 | Siemens Ag | METHOD FOR CONTACTLESS MEASUREMENT OF THE POTENTIAL DEVELOPMENT IN AN ELECTRONIC COMPONENT AND ARRANGEMENT FOR PERFORMING THE METHOD |
DE2823642A1 (en) * | 1978-05-30 | 1980-01-03 | Siemens Ag | METHOD FOR CONTACTLESS POTENTIAL MEASUREMENT ON AN ELECTRONIC COMPONENT |
-
1981
- 1981-09-30 DE DE19813138929 patent/DE3138929A1/en not_active Withdrawn
-
1982
- 1982-07-15 US US06/398,542 patent/US4514682A/en not_active Expired - Fee Related
- 1982-08-17 DE DE8282107490T patent/DE3276035D1/en not_active Expired
- 1982-08-17 EP EP82107490A patent/EP0075709B1/en not_active Expired
- 1982-09-27 JP JP57168239A patent/JPS5871542A/en active Granted
Patent Citations (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2946002A (en) * | 1958-02-17 | 1960-07-19 | Kingston Electronic Corp | Signal-pickup test probe |
US3445708A (en) * | 1967-02-06 | 1969-05-20 | Gen Electric | Electron diffraction unit |
US3531716A (en) * | 1967-06-16 | 1970-09-29 | Agency Ind Science Techn | Method of testing an electronic device by use of an electron beam |
US3448377A (en) * | 1967-10-12 | 1969-06-03 | Atomic Energy Commission | Method utilizing an electron beam for nondestructively measuring the dielectric properties of a sample |
US3549999A (en) * | 1968-06-05 | 1970-12-22 | Gen Electric | Method and apparatus for testing circuits by measuring secondary emission electrons generated by electron beam bombardment of the pulsed circuit |
US3760180A (en) * | 1971-10-14 | 1973-09-18 | Siemens Ag | Electron-beam micro-analyzer with an auger electron detector |
US3796947A (en) * | 1973-02-27 | 1974-03-12 | Bell Telephone Labor Inc | Electron beam testing of film integrated circuits |
US4179604A (en) * | 1978-09-29 | 1979-12-18 | The United States Of America As Represented By The Secretary Of The Navy | Electron collector for forming low-loss electron images |
US4355232A (en) * | 1979-05-28 | 1982-10-19 | Hitachi, Ltd. | Apparatus for measuring specimen potential in electron microscope |
US4417203A (en) * | 1981-05-26 | 1983-11-22 | International Business Machines Corporation | System for contactless electrical property testing of multi-layer ceramics |
Non-Patent Citations (2)
Title |
---|
H. P. Feuerbaum, VLSI Testing Using the Electron Probe , Scanning Electron Microscopy 1979 pp. 285 296. * |
H.-P. Feuerbaum, "VLSI Testing Using the Electron Probe", Scanning Electron Microscopy 1979 pp. 285-296. |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4658137A (en) * | 1983-10-17 | 1987-04-14 | Texas Instruments Incorporated | Electron detector |
US4812651A (en) * | 1986-11-13 | 1989-03-14 | Siemens Aktiengesellschaft | Spectrometer objective for particle beam measuring instruments |
US5093616A (en) * | 1989-09-14 | 1992-03-03 | Hitachi, Ltd. | Voltage measurement method using electron beam |
US6359451B1 (en) | 2000-02-11 | 2002-03-19 | Image Graphics Incorporated | System for contactless testing of printed circuit boards |
US6621274B2 (en) | 2000-02-14 | 2003-09-16 | Image Graphics Incorporated | System for contactless testing of printed circuit boards |
EP3203494A4 (en) * | 2014-09-24 | 2018-06-06 | National Institute for Materials Science | Energy-discrimination electron detector and scanning electron microscope in which same is used |
US20180082829A1 (en) * | 2016-01-21 | 2018-03-22 | Japan Synchrotron Radiation Research Institute | Retarding potential type energy analyzer |
US10319578B2 (en) * | 2016-01-21 | 2019-06-11 | Japan Synchrotron Radiation Research Institute | Retarding potential type energy analyzer |
Also Published As
Publication number | Publication date |
---|---|
EP0075709A2 (en) | 1983-04-06 |
EP0075709A3 (en) | 1983-06-29 |
JPS5871542A (en) | 1983-04-28 |
JPS6352428B2 (en) | 1988-10-19 |
DE3276035D1 (en) | 1987-05-14 |
DE3138929A1 (en) | 1983-04-14 |
EP0075709B1 (en) | 1987-04-08 |
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AS | Assignment |
Owner name: SIEMENS AKTIENGESELLSCHAFT; BERLIN AND MUNICH, A G Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:FEUERBAUM, HANS-PETER;REEL/FRAME:004026/0604 Effective date: 19820708 |
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LAPS | Lapse for failure to pay maintenance fees | ||
STCH | Information on status: patent discontinuation |
Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362 |
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Effective date: 19890430 |